Researchers have shed light on formerly unknown details about renowned French Impressionist Claude Monet's 1883 painting, titled 'Etretat
Led by astronomer and physics professor Donald Olson, a team of researchers from Texas State University applied their distinctive brand of forensic astronomy to Monet's masterpiece.
Olson said that Monet, founding member of the Impressionist movement, painted a dramatic scene on the Normandy coast, and the canvas shows the orange disk of the Sun sinking toward the horizon near a spectacular line of cliffs.
Olson also explained that he likes to use astronomy to show students how science can solve real-world puzzles, and wondered if his team could use the dramatic rocks in the landscape and the position of the setting sun to determine where and when, specifically, Monet created this beautiful masterpiece.
Monet painted a series of paintings of the Normandy coast during his three-week visit to the area during the winter of 1883.
With Etretat: Sunset, Monet painted a cliff known as the Falaise d'Aval along with the arch Porte d'Aval overlapping a tall, needle-shaped rock spire known as Aiguille (the Needle) that stands just offshore.
Key to the image, however, is a low, setting sun just to the right of the landforms. Of all the paintings Monet painted at Etretat, this is the only canvas that includes the disk of the sun, and that one detail opens the door to date the scene precisely.
To determine on which days in February the sun would've set in the proper location for Monet to capture in his painting, the team of Texas State researchers traveled in August 2012 to France.
Previously, art historians wrote that the scene had been painted by Monet standing just a few yards from a small arch called Porte d'Amont to the northeast of Etretat.
But Olson quickly determined that for an observer in that location the Porte d'Aval and Aiguille do not overlap, and another rock formation is visible through the Aval arch-clearly a different view from Monet's.
The research team made extensive topographic measurements of the terrain at Etretat. To determine the exact locations where Monet stood, they walked systematically from one end of the beach to the other at low tide, armed with postcard-size reproductions of about a dozen Monet paintings of the area. They located the precise vantage points from which Monet created the various paintings.
The Texas State team found that the view matched the scene depicted in Etretat: Sunset at only one location-a spot 425 yards from the Porte d'Amont on a rocky beach under an overhanging cliff.
The researchers used planetarium software to compare the modern sky to that of the 19th century.
Since the Texas State team visited in the summer, the sun was out of position to replicate the sunset from Monet's painting. The waxing crescent moon, however, offered a convenient stand-in during the early evening hours, and star-fields became visible after moonset.
By determining an astronomical coordinate called declination for the moon and stars, they were able to calculate the sun would have set along that path on Feb. 5, 1883.
Allowing for some uncertainty, the researchers concluded that the correct date must fall in the range between Feb. 3 and Feb. 7, 1883.
The group then combed through letters Monet wrote from Etretat during his stay, along with weather records and tide tables from February of 1883 to confirm their date.
They discovered that on Feb. 3 Monet was working on nearby Jambourg Beach and that the artist spent all day Feb. 4 entertaining his visiting brother.
The tides of Feb. 6 did not match the painting, and Monet's letters show that he paid close attention to the tides. On Feb. 7 cloudy weather and rain storms began.
Through the process of elimination, the calculated date of Feb. 5 is the only one remaining that matches the sun's position, the weather and the tide level in the painting.
Armed with that knowledge, the Texas State team used the height of the needle-like Aiguille formation to calculate the exact time from the altitude of the sun above the horizon.
Olson said that they were able to determine the month, day, hour and precise minute, accurate to plus or minus one minute, when Monet was inspired by that beautiful scene, which is on Feb. 5, 1883 at 4:53 p.m. local mean time.
The study is published in the February 2014 issue of Sky and Telescope magazine.